The present invention relates to multilayer ceramic devices, and more particularly to multilayer tapered transmission line devices suitable for large bandwidth applications.
It is popular in the art to employ transmission lines for signal propagation through the layers of a multilayer ceramic package. For instance, it is common to build multiple layers of such devices by screen printing a conductive paste (e.g., including silver, gold, copper, nickel, palladium, platinum or the like) on layers of a ceramic green tape according to a predetermined pattern. The layers are co-fired to form a dense ceramic package. Vias are typically formed for bridging electrical communication between conductive layers.
In many radio frequency applications, there is a need for impedance matching over a broad range of frequencies. One desirable approach is to employ a tapered transmission line, as is known in the art. However, it has been found that ceramic packaging size constraints have prohibited the optimal design of tapered transmission line devices. Accordingly, there is a need for an improved impedance matching transformer, which is useful over a broad range of frequencies and which can be incorporated into multilayer ceramic packaging for minute size applications.
Illustrative examples of other technological advances in the present general field include that disclosed in U.S. Pat. Nos. 5,119,048; 5,140,288; 5,949,304; and 5,977,850, all of which are hereby expressly incorporated by reference.